You should determine the best vitamin C dosage by speaking with your doctor or pharmacist. There is evidence suggesting that humans may benefit from much higher amounts than what is generally suggested as a daily serving, but this vitamin can cause an overdose if taken in very high quantities. Only a trained medical professional can give you personalized information on dosage. When in doubt, follow the instructions listed on the vitamin's container or packaging.
The most common way of determining the best vitamin C dosage is to check the recommended daily value on the bottle your vitamins come in. There should be a serving size suggestion along with information on how many times per day to take it. This number is usually much smaller than what can be tolerated by the human body, and some experts claim much higher amounts would be beneficial.
If you feel that you need a higher vitamin C dosage to boost immune function, you should speak with a doctor, pharmacist, or naturalist to discuss the maximum dosage you can handle. Although it is difficult, it is possible to overdose on vitamin C. If you are pregnant, do not take more than the recommended daily dosage unless instructed to do so by your doctor.
You may have to begin by increasing your vitamin C dosage slowly so that any potential side effects can be monitored. Only do this under the supervision of a medical professional. In most cases, an adult human body can tolerate up to 2,000 mg of vitamin C per day, but your doctor may prescribe more if you are deficient.
There is some evidence suggesting that amounts of more than 200 mg taken at one time cannot be used by the body, and the excess vitamin exits through urine. No studies have confirmed whether or not taking high doses is beneficial. This is why oral vitamin C therapy in the treatment of cancer and other diseases does not seem to work effectively. Intravenous Vitamin C can be used in very high amounts and is better utilized by the body.
Although overdose is rare, some people may have adverse reactions to vitamin C, especially when taken in high amounts. Symptoms can include headache, stomach upset, heartburn, cramps, diarrhea, and kidney stones. If you have any of these symptoms and have been taking more than the recommended vitamin C dosage, discontinue use of any supplements and contact your doctor or pharmacist.